本文選題：細(xì)菌 + 胞外多糖　； 參考：《南京農(nóng)業(yè)大學(xué)》2015年碩士論文

【摘要】：多糖是一種重要的生物大分子,它擁有各種各樣的特異性的結(jié)構(gòu),具有多種生理生態(tài)功能,在工農(nóng)業(yè)生產(chǎn)及醫(yī)療、制藥等領(lǐng)域具有非常廣泛的應(yīng)用。微生物來(lái)源的多糖具有潛在的應(yīng)用價(jià)值和發(fā)展前景,其研究越來(lái)越受到人們的重視。因此,研究土壤產(chǎn)胞外多糖細(xì)菌有著重要的理論和現(xiàn)實(shí)意義。鑒于此,本課題擬從紅壤中篩選高效產(chǎn)胞外多糖細(xì)菌,并研究細(xì)菌的遺傳多樣性和功能多樣性,探索產(chǎn)多糖細(xì)菌的培養(yǎng)基營(yíng)養(yǎng)和條件;并通過(guò)產(chǎn)多糖細(xì)菌對(duì)環(huán)境條件抗性的研究,來(lái)尋找能不受外部條件太多限制的產(chǎn)多糖菌株,使產(chǎn)多糖細(xì)菌在土壤改良中發(fā)揮作用。研究結(jié)果不僅有助于對(duì)產(chǎn)多糖細(xì)菌生物多樣性的深入認(rèn)識(shí),豐富產(chǎn)多糖細(xì)菌資源庫(kù)、基因庫(kù),還能夠?yàn)樵擃惥N代謝機(jī)制及在各領(lǐng)域的應(yīng)用提供試驗(yàn)依據(jù)。也可為后續(xù)試驗(yàn)研究提供菌種資源。本文以來(lái)源于紅壤的207株產(chǎn)多糖細(xì)菌為材料,采用苯酚-硫酸法測(cè)定發(fā)酵液中可溶性多糖,篩選獲得30株多糖高產(chǎn)菌株,對(duì)高產(chǎn)菌株進(jìn)行了細(xì)菌菌落形態(tài)及其對(duì)環(huán)境適應(yīng)性的研究,分析了碳氮源對(duì)高產(chǎn)菌株多糖產(chǎn)量的影響,并對(duì)其中26株高產(chǎn)胞外多糖細(xì)菌進(jìn)行了 16SrDNA序列測(cè)定及系統(tǒng)發(fā)育關(guān)系的研究。研究結(jié)果如下:1、菌落形態(tài)學(xué)的研究表明,菌落呈白色或微黃色,有粘性,透明或半透明,形狀圓形突起,大小在2.0-5.2 mm之間;2、大部分菌株正常生長(zhǎng)的pH范圍在6-8之間,溫度在20℃-30℃之間,滲透壓范圍在1%—2%,大部分菌株對(duì)氨芐青霉素有抗性,對(duì)四環(huán)素和利福平無(wú)抗性;同時(shí)還發(fā)現(xiàn),菌株2-7、菌株2-34、菌株3-3和菌株1-22在酸性、堿性、低溫和高鹽溶液的環(huán)境中都具有很強(qiáng)的抗性。可作為后續(xù)試驗(yàn)土壤改良的菌種資源。3、碳氮源對(duì)菌株多糖產(chǎn)量影響的研究結(jié)果表明,菌株4-27-1、菌株5-3、菌株4-8、菌株4-30和菌株4-27-2生長(zhǎng)的最佳碳源和氮源分別為蔗糖和硫酸銨;糖蜜是菌株4-8和菌株4-27-2的次選碳源;菌株5-3和菌株4-27-2也可選擇硝酸銨作為氮源;菌株6-20可選擇大豆粉作為氮源。4、16S rDNA序列分析結(jié)果表明,26株細(xì)菌分別隸屬于7個(gè)屬,菌株1-1和菌株1-3屬于芽孢桿菌屬(Bacillus);菌株1-22、菌株2-7和菌株3-3屬于沙雷氏菌屬(Serratia);菌株1-35、菌株5-12和菌株6-22屬于伯克霍爾德氏菌屬(Burkholderia);菌株2-22屬于中慢生根瘤菌屬(Mesorhizobium);菌株6-34屬于根瘤菌屬(Rhizobium);菌株3-15、菌株4-27-1、菌株4-27-2、菌株4-30、菌株5-3、菌株5-19、菌株5-25、菌株5-33共8株屬于類芽孢桿菌屬(Paenibacillus);菌株2-26、菌株2-34、菌株3-25、菌株4-5、菌株4-6、菌株4-8、菌株4-9、菌株4-39共8株屬于劍菌屬(Ensifer)。初步確定產(chǎn)胞外多糖能力最強(qiáng)且菌株來(lái)源最多的是類芽抱桿菌屬(Paenibacillus),其中菌株4-27-1的多糖濃度最高為3.21 mg/ml;產(chǎn)胞外多糖能力相對(duì)較弱的是根瘤菌屬(Rhizobium),其多糖濃度為0.70mg/ml。
[Abstract]:Polysaccharide is an important biological macromolecule, it has a variety of specific structures, has a variety of physiological and ecological functions, and has a wide range of applications in industrial and agricultural production, medical treatment, pharmaceutical and other fields. Polysaccharide from microbial sources has potential application value and development prospect, and its research has been paid more and more attention. Therefore, the study of soil extracellular polysaccharide bacteria has important theoretical and practical significance. In view of this, the aim of this study was to screen the highly efficient extracellular polysaccharide producing bacteria from red soil, to study the genetic diversity and functional diversity of the bacteria, and to explore the nutrition and conditions of the culture medium for the polysaccharide producing bacteria. By studying the resistance of polysaccharide-producing bacteria to environmental conditions, we can find out the polysaccharide producing strains which can not be restricted by external conditions, so that the polysaccharide-producing bacteria can play an important role in soil improvement. The results can not only help to understand the biological diversity of polysaccharide producing bacteria, enrich the resource bank and gene pool of polysaccharide producing bacteria, but also provide experimental basis for the metabolic mechanism of this kind of bacteria and its application in various fields. It can also provide strain resources for further experimental research. In this paper, 207 strains of polysaccharide producing bacteria from red soil were used as materials to determine soluble polysaccharides in fermentation broth by phenol-sulfuric acid method. The morphology of bacterial colony and its adaptability to environment were studied, and the effects of carbon and nitrogen sources on polysaccharide yield of high-yielding strains were analyzed. The 16SrDNA sequence and phylogenetic relationship of 26 strains of high-yielding extracellular polysaccharide bacteria were studied. The results were as follows: 1. The colony morphology showed that the colony was white or yellowish, sticky, transparent or translucent, with a circular protuberance, ranging in size from 2.0 to 5.2 mm, and the pH range of normal growth of most strains ranged from 6 to 8. The temperature ranged from 20 鈩，

本文編號(hào)：1988795